Centrifugal pump.



PATENTED OCT. 2

W. I. BETTIS. GENTRIFUGAL PUMP.

APPLICATION FILED mums, 1905.

' 3 SHEETS-SHEET 1.

auuenfoz 5y wrheyo' Wit Meow:

. PATENTED OCT. 2, 1906. I w. 1. BETTIS.

GENTRIPUGAL PUMP.

APPLICATION FILED J'ANJB, 1905.

3 SHEETS-SHEET 2.

. M 9 .3 wfi? I a W m/ 7% PATENTED OCT. 2, 1906.

W. I. BETT-IS. GENTRIFUGAL PUMP.

APPLICATION FILED JAN.18, 1905.

3 SHEETS-SHEET 3.

8 wan To:

Fdliam Ifielfls,

51 all'brrwya -Improvements in Centrifugal Pumps,

UNITED STATES PATENT OEEIOE.

TO HUGH HAMILTON,

OF HOUSTON, TEXAS.

CENTRIFUGAL PUMP.

Specification of Letters Patent.

Patented Oct. 2, 1906.

Application filed January 18, 1905; Serial No. 241,666.

To all whom it may concern: 1 Be it known that I, WILLIAM IRVIN BET- TIS, a citizen of the United States, residing at Houston, county of Harris, and State of Texas,.have invented certain new and useful which the following is a specification.

My invention relates to centrifugal pumps in which a rotary impeller,- having a fluid-entrance at the eye, discharges into a surrounding discharge-chamber; I

More particularly the invention relates to centrifugal pumps of the class in which'an incased impeller composed of side disks and interver ng' radial or tangential vanes receives fluid at the eye and dischar es it into a surrounding volute or annular dischargechamber which communicates with chambers formed in a fixed casing. inclosing the im eller. I

'l he object of my invention, generally stated, is to reduce or eliminate the loss of energy due to'shock of entrance and also the loss of energy due to friction at the periphery of the impellerdue to the drag at the junc ing discharge-chamber.

Further objects of my invention are to re-' lieve the impeller from detrimental pressure at the eye or entrance, as well as on its sides,

to (prevent leakage at the eye of the impeller also at'the discharging portion. thereof, to reduce friction at the sides of the impeller, and generally to increase'the efficiency of the pump Without complicating its construction.

In the general design of my improved pump the fluid is driven from an incased impeller through a contracted orifice or throat at a velocity corresponding to the difference in pressure between the pressure within the im eller and that in the discharge-casing or vo ute, and the chambers of the pump-casing are em tied and kept clear of fluid by centrifuga action, as well as by the action of the fluid passing through the throat of the impeller and operating as an. injector. The fluid enters the impeller through devices which reduce the area of the entrance-port, and conse uently increase the initial velocit of the fluid just as it,enters the im eller. T ese devices are also arranged to deliver the fluid to the impeller in a direction corresponding to the direction in which the imag at the eye and the loss of energy due to eller is rotating, by which arrangement the shock of entrance is obliterated or greatly reduced.

In the operation of my proved pump the impeller and the chambers .of its fixe casing are first filled with the fluid to be, pumped in order to properly prime the pump, and then the pump is started and the,

chambers of the casing are automatically.

emptied, and in the continued operation of.

the pump a vacuum is maintained in thecas ingchambers, thus relieving the impeller from side friction; In order to insure that;

there shall be no leakage of fluid from the impeller. into the casing-chambers, I providenovel devices which interpose a resistancebetween the impeller and the chambers ofthe casingand which cause the fluid to flow along the lines of least resistance, which is through the impeller.

A more detailed description of the opera-- tion of the. pump and of the specific 'or pre-; ferred construction thereof will be given later on. tion between the impeller and the surround- In the accompanying drawings, Figure 1 Fig. 2 is a detail view-1n perspective, illustrating the relation between the-vanes of the rotary impeller and the stationary or inlet vanes central section through the castin containing the inlet-passages and the i et-vanes. 'Fig. 2 shows a sectionthrough the inletvanes, and passages on the line a, a; of Fig. 2,-

and this fi ure also shows one ofjthe impellershows a horizontal central-section of a cen-. trifugal pump embodying my improvements vanes. I Fig.3 is a detail view of a portion of the rim or periphery of the impeller. Fig. 1.

is a view, partly in side elevation and-partly 'invertical section, on the line 4 4 of Fig. 1.

Fig. 5 is a detail view in-section of a -modifi-. cation in which the inlet-vanes are arrangedto deliver the fluid to the impeller-vanes horizontally instead of tangentially, as in Fig. 1. Fig. 6-is a side elevation of the inlet-vanes looking in the direction of the arrow-in Fig. 5.

Fig. 7 'shows a side elevation of the pump shown in Fig. 1. Fig. 8 is a view in vertical section of a portion of a centrifugal ump, showing a modification wherein the uid is delivered at the eye to one side of the im eller only and certain parts illustrated-in ig. 1

are omitted. Inthis figure I have also shown an e ualizing-pipe connectin the casingcham ers on opposite sides the impeller and serving to equalize the pressure in these chambers.

The impeller A, Fig. 1, is composed of two side plates or disks (1, arranged a suitable dis tance apart and connected by intervening vanes B, which divide the space between the disks intoa series of chambers B, through which the fluid passes. The vanes are connected with a centrally-arranged hub C, fast on the drivingshaft D. The hub, vanes, and disks are all rigidly connected together and rotate in unison. The periphery of the impeller is v tapered outwardly, and the outer edges of the disks are arranged a suitable distance apart to form a contracted annular discharge orifice or throat E, which runs closev to the throat f of corresponding width in the volute or annular discharge-chamber F. In

' the pump having a double supply, as illustrated in Fig. 1, the vanes B are branched or bifurcated and extend inwardly on opposite sides of the hub 0.. The outer portions of the chambers B are of approximately the same width from the edge of the hub C to the throat E, the inner sides of the disks being nearly parallel, as shown in Fig. 1, until they approach close to the throat, where the sides are curved or tapered toward the throat. In

. this way the chambers are made wide just inside the throat, and a pressure is produced at the throat, while the velocity of the fluid is greatly reduced. As the velocity of the fluid within the impeller is reduced at the outer portion of the impeller-chambers the friction of the fluid on the walls of the impeller-chamhers is materially reduced, and thus the efficiency of the pump is enhanced.

The fluid enters the impeller through the supply-passages on opposite sides thereof. These passages on each side are formed in a casing G, provided with an entrance-port g, which communicates with a chamber g, surrounding the driving-shaft D and having a .hub 9 extending within the plane of the impeller and beyond the inner edges of the impeller-vanes to the hub C. The fluid which enters at g passes into the annular chamber g and is directed into the impeller in such manner as to partake of the direction of movement of the impeller and to be delivered at the general angle in which the impeller-vanes are arranged. In this way the loss of energy due to shock of entrance is avoided, or at any rate, very materiall reduced.

I preferably, as s own in Fig. 1, arrange a series of vanes H in the su plyepassages at the inner ends of the impel er-vanes, which are so constructed as to reduce the area of the entranceort, and consequently increase the initial ve locity of the fluid. The construction is also such as to change the direction of flow of the fluid to the impeller in the manner before stated, and thus reduce or obviate entirely the loss of energy due to the shock of entrance. The form of the vanes is clearly indicated in Fig. 2. It is also indicated in Fig. 4, where, as it will be seen, the casing G is provided with an annular series of openings it, through which the fluid passes, these openings being separated by vanes h", which are properly inclined to direct the fluid in the proper direction in the manner before described. The construction of the casings of the entrance-passages and of the vanes H on opposite sides of the ump are precisely the same as indicated in ig. 1. It is of course desirable that there should not be sudden changes in velocity. The vanes H, by reducing the area of the entrance-ports, increase the velocity of the entering fluid, so that it approaches the velocity of the fluid carried around by the inner ends of the impeller-vanes.

In Fig. 8 I have shown a construction in which the fluid is admittedto one side only of the ump. In this figure, G indicates the supp y-passage, which delivers to the vanes B in a direction in line with the general direction of the movement of the vanes. In this case the vanes H are omitted, as the pum will operate fairly well without the vanes H although I prefer to use them.

In Fig. 5 the impeller-vanes are prolonged outwardly and their inner edgesare substantially radial, while the vanes H deliver horizontally to the impeller-vanes; but in this case also the fluid leaves the vane H at an increased velocity and in a direction corresponding to the disposition and movement of the impeller-vanes.

Referring again to Fig. 1, it will be observed that the impeller is inclosed in a fixed casing, the casing in this instance consisting of two annular frame pieces or sections I on opposite sides of the impeller. At their periphery the casing-sections are bolted to the flanges e of the volute or annular discharge-chamber F. The edges of the casingsections are inclined or tapered correspondingly with the ta ered periphery of the impeller, being paral el therewith, but. arranged a short distance therefrom,-leaving a clear but narrow s ace for the passage of fluid from the chambers J of the casing to the dischargechamber F. The arrangement at this part of the pump is quite im ortant and will be hereinafter again referre to.

A careful inspection of Fig. 1 and also an inspection of Fig. 3 will show that the periphery of the impeller is formed with narrow radial grooves 11 for a purpose resently explained. The chambers J of tl ie casing are annular and in Fig. 1 are on opposite sides of the impeller. They communicate with the throat E and also the throat f at the periphery of the impeller through the narrow annular passages a: above referred to. The casingsections I carry radiallyarranged baffleplates or ribs K, which are for the purpose of preventing a rotary movement of the water within the chambers J when the pump is first started.

In the operation of my improved pump the impeller, casing-chambers, and sup passages are all first completely filled with the fluid to be pumped in order to prime the pump. Then a rotary movement is imparted to the impeller, and the fluid is discharged through thethroat of the impeller, the chambers J being at this time filled with the fluid, which not only produces a pressure on the impeller, but also creates a detrimental side friction which it is desirable to avoid. In my improved pump soon after the rotary movement of the impeller commences the fluid in the chambers J passes out through the passages :20 b gravity by the injector force caused by t e rush .of water through the throats E and f and also by the centrifugal action. caused in the passages a: by the rapid rotation of the inclined eriphery of the impeller. In this .way tiie chambers J are uickly emptied and vacuums are formed in the casing-chambers, the impeller thus being relieved entirely of friction on its sides. If by reason of increased-pressure inthe dis charge-chamber or any other cause the fluid tends to pass inwardly through the passages ac to the chambers J, it will pack by capillary.

attraction in these passages along the overhanging faces of the casing-sections and will be caught by the rotating peri hery of the impeller and expelled through tl fe'passages :n out into the throat of the volute or dischargecasing. This expelling action is sometimes, of course, accompanied by the expelling action due to the rush offluid through the throats E andf; but even though there should be no injector action such as above mentioned the centrifugal force would be sufficient to prevent the passage of the fluid to the casing-chambers. The grooves a on the periphery of the impeller assist in thus catching the fluid and discharging it, although a plane ungrooved or unribbed periphery would work fairly well. Any ten ency for the pump to leak at the junction of the throats E and f is compensated for by this construction, because any tendency to leak back into the pump-casing is obviated or compensated for by the action above described, which throws any fluid which enters the passages :0 into the throat of the discharge-chamber.

The arrangement at the eye of the pump is such as to cause the fluid to pass easily into the chambers of the impeller which oflers the least resistance to the fluid, so that there is little tendency for the fluid to leak at the eye into the casing. To avoid any possibility of leakage at the eye, I provide the devices indicated in Fig. 1. 'As there shown entering at the eye of the pum the casing G on each side of the pump is formed with an annular chamber L, within which is arranged an annular plate or ring M, bolted to the impeller and rotating therewith. This annular plate extends into the chamber L beyond the inner edges of the casing-section, andit is formed with radial ribs Z, arranged closeto without touching the outer side of the casing-section next the chamber L. The casing G within the annular chamber L is formedwith stationary radial ribs Z, lying close to the outer face of the plate M. These ribs terminate a short distance from the outer wall of the chamber L and are overlapped by small radial ribs m on the plate M. Any fluid which may leak at the oint y will pass into the chamber L and will tend to pass around the outer edge of the plate M and into the chamber J through the joint 2. This is the only way b which the fluid can enter the chamber J,- ut this is prevented in the following way: As the impeller rotates any fluid which may pass out at thejoint y and into the chamber L will be thrown outward by centrifugal force and carried around at the-outer endof the chamber L, and this centrifugal force is such that no fluid will pass down into the joint 2.

.In this way a rotary fluidseal is formed which will absolutely prevent any fluid from into the chambers of the casing. There ore it will be understood that after the pump has been set into operationand the fluid has been eX- pellecl from the chambers of the casing no fluid can reenter said chambers as long as the pump isin operation, because it cannot leak at the eye, for the reasons just described, and it cannot pass into the chambers at the periphery of the pump, for the reasons before explained. Thus I-am enabled to use an incased or housed pump so constructed as to prevent all leakage between the impeller andvolute or dischar e-chamber, and at the same time I am enab ed to relieve the impeller from any pressure or friction which would be caused by the presence of fluid in the casingchambers. It has heretofore been attempted to relieve this side friction or pressure by depending on the injection action at the throat of the pump to withdraw the fluid from the casing-chambers and to employ mechanical packing at'the eye of the pump; but this is not sufficient, for the reason that a variation in the head of pressure in the discharge-chamber may stop the ejector action, which would cause the casing-chambers to immediately fill, while in my pump, even if the head varies and the injector action is reduced or suspended, the fluid is still kept out of the casing-chambers by the centrifugal action afforded by the special construction .of the periphery of the impeller and the portion of the casing surrounding the impellers periphery.

I have not dwelt upon the special construc tion or arrangement of the vanes of the impeller as these may be arranged radially, tangentially, or may be curved; but I prefer the construction and arrangement illustrated.

The fluid need not necessarily be admitted to the opposite sides of the impeller, though this is preferred.

In Fig. 8 the construction of a ump Where the entrance is only at one sidh is clearly illustrated. The pressure in the chambers J on opposite sides of the impeller may be equalized by means of a pi e connection 0.

The general principles 0L construction of the pump illustrated in Fig. 1 are present in the pump illustrated in Fig. 8 so far as the means provided for emptying the casing chambers or for maintaining a vacuum therein are concerned. In the pump illustrated in Fig. 8, however, I have omitted the vanes H at the entrance to the impeller and have also omitted the devices for preventing leakage at the eye from the impeller into the casing-chambers, as I find that under some conditions there is not necessarily any leakage or any tendency to leak at the eye, because the path which leads from the supplyentrance to the impeller is that of least re sistance.

It will be observed also that both in Figs. 1 and8 the joint at y is a horizontal one and there is no tendency for centrifugal action to throw the fluid throughthis joint, as there would be if this joint were a vertical one.

It will be observed that the vanes 18 do not enter the throat E, in which there is an unobstructed rotary whirlpool or diffusionchamber. The edges of the vanes are thus held away from the fluid in the stationary chamber, and thus the drag at the periphery of the impeller, often found in pumps of this class, is greatly reduced.

I claim as my inventionl. A centrifugal pump comprising an impeller having an annular contracted dischargethroat formed in its tan-cred periph cry, a discharge-chamber sur ounding the im eller and communicating tn-csewith, and a fl rted chambered. casing inclcsing the impeller and having a tapered or inclined communication between its char -hers and the discharge-chamber.

2. A centrifugal pump comprising an in closed impeller having an annular cont ed discharg -throat formed in its tapered periphery, an annular discharge-chamher surrounding the impeller and h g an annular contracted threat communicating with. the throat of the impeller and a fixed chambered casing inclosing the impeller and. having a tapered or inclined communication on opposite sides of the impeller between its cliamhers and the dischargechamher.

3. A centrifugal pump comprising impeller having a tapered periphery and an annular contracted discharge-throat, an annular discharge-chamber having a contracted throat communicating with the throat of the impeller, a fixed chambered casing for the impeller and an annular passage along the t'a cred periphery of the impeller for establis ing a communication between the champers of the casing and the discharge-cham- 4. A centrifugal pump com rising an impeller having a tapered radial y-grooved periphery, and discharging through its periphcry, a discharge-chamber surrounding the impeller and communicating therewith, and a fixed chambered casing inclosin the impeller and communicating with the ischargechamber by a passage along the grooved periphery of the impeller. I

5. A. centrifugal pump comprising. a rotary impeller communicating with a dis charge-chamber surrounded by a casing and having a peripheral surface which moves at a higher speed than the vanesand which is constructed to throw fluid therefrom by cen-- trifugal action into the discharge-chamber, and means for preventing leakage at the eye of the impeller.

6. A centrifugal pump comprising a rotary impeller having a tapered periphery, a discharge-chamber communicatlng with the impeller, a fixed, casing surrounding the impeller and havin vacuum-chambers communicating with the dischar achamber, and vanes at the eye of the impe ller for reducing the entrance-port and thus increasing the velocity of the entering fluid.

7. A. centrifugal pump, comprising a ro tary impeller, a discharge-chamber communicating therewith, a fixed casing at the side of the impeller which is emptied. by the intpeller and contains a chamber communicating witli the discharge-chamber, a seal at ilLllG e e of the impeller and means within said fixed casing for preventing any centrifugal action, thereby breaking the pull of lluid through the seal the eye oi theimpeller when the pump is first started.

8. A centrifugal pump, comprising a retary impeller, a dischargechamber communicating therewith, a fixed clian bered cas ng surrounding the impeller and communicating "a to. the discharge-chamber, fined rihs within. the chambered casing, "for preventing the rotation of the fluid therein when starting the pump, a seal at the eye of "the impeller, and ineaiis for exhausting the fluid from said chambered casing after the pump is started.

Q. A centrifugal pump comprising r-otary impeller, dischargemhamber communicating therewith, a fixed chambered casing rounding the impeller and communicating mth the dischargewhamher, fixed ribs within the chambers for preventing the rotation of fluid therein, and a centrifugal water seal tary impeller havin impe at the eye of the im eller for preventin the entrance of fluid to he chambers of the ed casing.

10. A centrifugal pump comprising a r0- tary impeller, a fixed chambered casing theretary impeller, 'a. so arge-chamber communicating therewith, a chambered casing surrounding the impeller, a casing containing a supply-passage at the eye of the impeller and formed with an annular chamber around theeye, and aribbed plate carried by the impeller and operating in said annular chamber for producing a centrifugal water seal to pre-I vent leakage of the ump at the eye.

12. A centrifuga pumfi comprising, a roer-vanes and sides extending beyond t e outer tips of the vanes to provide between them a rotary whirlpoolchamber, in combination with a dischar echamber, communicating with the, Whirlpool-chamber, a fixed casing inclosmg the impeller and vanes in the eye of the impeller for increasing the velocity of the entering fluid and for directing the fluid to the impeller-vanes.

.13. A rotary impeller having impellingvanes and a contracted discharge-throat in its rim outside the tips of the vanes so proportioned as to gradually increase the area or capacity, of the throat radially outward and thus graduall decrease the discharge velocity of the uid and so providing a rotary whirlpool or diffusion chamber in the rim of v the impeller incombination with the dischar e-chamber or volute surrounding the impe ler. Y

14. A centrifugal pump comprising a rotary im eller communicating with a discharge-chamber surrounded by a casing and having means on its eripher moving at a higher speed than -t e impe ler-vanes and adapted to throw fluid therefrom by centrifugal action into the discharge-chamber.

15. A centrifugal pum comprising an impeller having. an ann ar contracted d1scharge-throat formed in its tapered periphery outside the tips of the im e ller-vanes to provide a rotary whirlpool or iffusion chamber, a discharge-chamber surrounding the impeller and communicating with the discharge-throat thereof, and a casing for the tapered periphery of the impeller, for the purpose specified.

16. A centrifugal pump, comprising a ro-' tary im eller communicatin With a discharge-c amber, surrounded y a casing at itssides and having'means'traveling in a path outside that traversed by the tips of the impeller-vanes adapted to throw fiuld therefrom' and prevent a backflow from the discharge-chamber by centrifugal action sufiicient to overcome a head due to the action of the impeller-vanes.

In testimony whereof I have hereunto subscribed my name.

WILLIAM IRVIN BETTIS. 

